Now that Steven Chu is no longer energy secretary he can more easily speak his mind about issues such as climate change and renewable energy. On Friday at an event at the Calgary Chamber of Congress in Alberta, Canada, the Nobel Prize-winning physicist took that opportunity to share his thoughts on U.S.-Canada energy relations.

Since Chu first became energy secretary in 2009 the Keystone XL pipeline and the tar sands oil that would run through it have dominated the energy discussion between the U.S and Canada. Chu emphasized in his remarks that he hopes the two countries can move past the pipeline issue and onto other important areas of opportunity, such as boosting cross-border transmission infrastructure.

“It’s unfortunately become a lightning rod that’s helped polarize lots of discussions,” he said about the pipeline.

At the event, which was held with former Canadian Minister of Environment, Jim Prentice, Chu also said he’d like to see more collaboration between Canada and the U.S. on renewable energy, including hydroelectric and wind power.

“Canada is blessed with incredible hydro resources. We have hydro resources in parts of the United States,” he said. “I would dearly love to see the hydro resources used well and for more trade of hydroelectricity back and forth between the United States and Canada.”

Regarding the controversial Keystone XL pipeline, which would carry 830,000 barrels a day of tar sands crude from Alberta to Texas, Chu said President Obama must factor in climate change when deciding on whether to approve the project.

Prentice, who was Canada’s environment minister when Chu was energy secretary, said disagreement over Keystone XL is putting at risk the energy relationship between Canada and the United States. He also said that at the end of the day he hopes President Obama sees the pipeline as being in the U.S. national interest.

“The oil that pipe will carry is produced in a neighboring democratic country that has as high environmental standards as any oil producer anywhere in North America,” Prentice said.

Chu called Alberta’s carbon tax — which funnels revenue collected from big emitters into a green-technology fund — a “stroke of genius” that should be pursued by others to speed up the transition to renewables.

Chu further stressed the importance of Alberta’s carbon tax when referring to the Keystone XL pipeline.

“There are concerns about the increased carbon emissions with that type of oil, that’s why I think what Alberta is doing with regard to that is an important point that should be brought to the attention of the White House,” Chu said.